This invention relates to levels such as those used by carpenters, masons or the like, and more particularly to a holder or cover for use in retaining a level-indicating vial within an opening formed in the web of a level frame.
It is known to mount a level vial within a pair of opposed notches provided in an opening formed in the web of a level frame which extends between spaced working surfaces of the level. One vial retaining system is shown in DeJong U.S. Pat. No. 3,738,015. In the DeJong patent, a pair of retainer caps are provided for affixing the level vial to the level frame. The retainer caps are adapted for mounting one on either side of the web, and each has a pair of hooks for engaging the web at a pair of opposed notches not occupied by the vial. This system involves the separate mounting of both retainer caps to the frame web, independent of any connection of the retainer caps to each other.
It is an object of the present invention to provide an improved vial cover structure which is not dependent on connection to the level frame web for maintaining the cover structure thereon. In accordance with the invention, a vial cover assembly for use in maintaining a vial in position within an opening formed in the web of a level frame includes a first vial cover member and a second vial cover member. The opening formed in the frame has a pair of opposed coaxial notches adapted to receive the ends of the vial. Interlocking means is formed on the first and second vial cover members for securing them to each other so that the web of the frame is sandwiched therebetween. Positioning means is engageable with the frame for fixing the position of the vial cover assembly relative to the frame when the first and second members are secured together as described. Vial-engaging means is provided for engaging the ends of the vial to maintain the vial in position within the notches, and for fixing the vial to the frame when the first and second members are secured together.
In a preferred embodiment, the first and second members are identical in construction, and are formed of a resilient plastic material. The interlocking means comprises a male projection provided on each of the first and second members, spaced oppositely from a female recess. The projection on one of the first and second members is adapted to be received within the recess provided on the other of the members for securing the first and second members together. Structure is preferably provided for allowing a snap-fit of the first and second members together. In a preferred embodiment, each projection includes a lateral protrusion formed at its outer end, which is engageable with a lip which in part defines the recess of the other member. A wall is spaced from the lip, and also in part defines the recess. The wall and lip cooperate to define a narrowed entryway into the recess. The protrusion formed at the outer end of the male projection is wider than the narrowed entry way into the recess, and a wedge-type leading surface is formed on the protrusion. Push-on insertion of the projection into the recess causes the leading surface of the protrusion to engage the lip and the wall spaced therefrom. Continued such movement causes deflection of the wall and of the lip, thus allowing passage of the protrusion into the recess over the lip. Thereafter, the lip and the wall return substantially to their original positions. A lateral biasing force is exerted on the projection by the wall defining the recess. This action urges an angled surface on the protrusion into engagement with an angled surface on the lip, to secure the first and second members together.
An opening is preferably associated with the member in which the recess is formed, which allows access of the tip of a screwdriver or the like for dislodging the protrusion from the lip so as to allow disassembly of the first and second members.
Also in a preferred embodiment, the positioning means engageable with the frame comprises the projections extending through a pair of notches not occupied by the vial. The projections engage the edges of the frame which form the notches, so as to prevent relative movement between the vial cover assembly and the frame when the first and second vial cover members are secured together.